Mathematical formulation of optical multicast with loss-balanced light-forest

In wavelength-division multiplexing (WDM) optical networks, multicast is implemented by constructing a light-forest, which is a set of light-trees with each light-tree rooted from the multicast source and terminated at a partition subset of the destination nodes. Quality of optical signal at each destination node is greatly affected by multicast routing scenario. To guarantee that different destinations in a multicast session can receive relatively equivalent optical signal quality, it is desirable to deliver the multicast traffic over a loss-balanced light-forest. A loss-balanced light-forest is composed of a set of light-trees with each light-tree having both bounded destination size and bounded source-destination distance. This paper studies multicast routing and wavelength assignment (MC-RWA) problem under loss-balanced light-forest constraint. The problem is formulated as an optimization model using integer linear programming (ILP). Numerical solutions to the optimization model can supply useful performance benchmarks for loss-balance-constrained optical multicast in WDM networks